Chair



Sept. 1, 1953 H. M. GRANLUND CHAIR Filed Jan. 9, 1951 INVENTOR H. N. GRANLUND H W M ATTORNEYS Patented Sept. 1, 1953 UNITED STATES FATENT OFFICE CHAIR Hakon Miirk Granlund, Oslo, Norway Application January 9, 1951, Serial No. 205,051 In Norway January 9, 1950 3 Claims. 1

The present invention relates to chairs, par ticularly chairs for offices, in which the adjustinent of the height of the seat is efiected by means of a helical spring and the subject matter of the invention is a simple, cheap and easily operated means for effecting the said adjustment.

The seat is carried by a stem slidably mounted in a guide in the foot portion of the chair, and according to the invention the stem is provided with protruding parts extending in between the windings in the helical spring which is freely rotatable on the top surface or the said guide or on a disc or the like on the same. The lifting and lowering of the stem with the seat then can be effected by a relative rotation between the stem and the spring, whereby the seat with the stem may be rotated while the helical spring is at rest, or the seat may be kept at rest and the helical spring rotated. The helical spring preferably is provided with a handle, an arm or the like by means of which it can be rotated or prevented from rotation. Such an arm may consist of an outwardly projecting extension of the top windin of the helical spring.

The drawing illustrates the foot, the stem for carrying the seat and the helical spring for adjustment of the height of the seat in a chair according to the invention.

In the drawing l indicates the legs of the chair with spider 2 carrying the guiding sleeve 3 for the stem It. The stem is slidable in the sleeve and is provided with cross pieces 5 and 6 extending in between windings of the helical spring i. At its lower end the sprin is provided with a ring 8 preferably secured to the spring and resting on a bearing surface at the top of the guiding sleeve 3 so as to make the spring easily rotatable. For

rotating of the spring or for securing oi the same against rotation, the upmost winding of the spring is extended so as to form an arm 0.

i0 indicates a mounting on top of the stern i for carryin the seat.

When the chair is in use and the stem consequently under load, the friction between the cross pieces 5 and 6 and the windings of the spring always is larger than the friction of the bearing ring 8 of the spring against the bearing surface on top of the sleeve 3, so that the seat can be rotated freely without alteration of the height of the stern and the seat.

I claim:

1. In a revolving chair, a foot portion including a guide, a seat-carrying stem rotatable in said guide, a helical spring surrounding said stem and freely rotatably mounted on the top surface of said guide, and protruding members on said stem extending outwardly between windings of said spring, the static friction between said protruding members and said spring bein greater than that between said spring and said guide.

2. A chair as claimed in claim 1, the helical spring being provided with an outwardly projecting handle.

3. A chair as claimed in claim 1, the helical spring being provided with a handle consisting of an outwardly projecting extension of the top winding of the helical spring.

HAKON MoRK GRANLUND.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,704,447 Schmid Mar. 5, 1929 1,862,755 Madsen June 14, 1932 

